Three-dimensional shape dependence of spin-wave modes in single FePt nanomagnets

We report the dependence of the intrinsic spin-wave spectra on the three-dimensional shape in single FePt nanomagnetic elements. In contrast to the well-known center and edge modes in flat, circular nanodisks, curved nanomagnets with identical nominal thickness and footprint exhibit a rich multimode spectrum with qualitatively different dependence on applied field, such as a low-frequency ``pinned'' mode. Dynamic micromagnetic modeling shows that the experimentally observed modes originate from different sections of the nanomagnet with vastly different demagnetization fields. Thus, controlled shaping of a nanomagnet in all three dimensions creates the possibility of magnetization dynamics by design.